Automatic case erector and sealing methods and apparatus now available in the marketplace, in order to cope with box speeds of 20 to 40 per minute, are long in length, and hence space consuming, generally complicated to operate, expensive, and use only hot melt adhesive systems for sealing the erected boxes. The case erecting and sealing systems now available and in use in particular suffer from a number of specific disadvantages which are discussed in some detail below.
Hot melt adhesives are much more expensive than and not as strong as cold cure adhesives.
Long case erector and sealer lines are expensive because they take up large amounts of expensive and valuable heated and weather protected space.
Currently available case erector and sealer apparatus are generally of high cost, complicated to operate, subject to frequent breakdown and expensive maintenance costs.
The suction cups used in conventional systems are subject to losing suction due to uneven case surfaces, score or crease lines, slots, dust pick-up and debris that may be found in normal case erecting environments.
Suction cup case erecting systems used in conventional case erecting equipment are somewhat delicate to operate and do not permit the cases to be moved rapidly about. This is because the inertia inherent in a typical case flat causes suction action used to grip the flat to be readily broken if the case is moved quickly from a standing position and quickly returned to a standing position.
Case erecting systems using suction cups, because of their delicacy, frequently fail to function and case erecting lines moving at 10 to 40 cases per minute must be shut down as soon as one case slips out of place. Following cases on the line quickly pile up, and consequently, the line must be stopped while the cases are placed back in position, all of which results in costly down time for the case erecting system.
Vacuum cup grips used in case flat erection to pull both sides of the case into a concave configuration, particularly cases made of recycled cardboard, which concave configuration tends to cause line jamming problems when the case enters the sealing stage of the case processing line.
The dust collected by suction cups must be filtered out of the suction system thereby creating considerable nuisance and expense. Further, if the filters are not cleaned or changed at appropriate intervals, suction systems lose vacuum and the line must be shut down.
Vacuum cup case handling lines have difficulty handling undesirable "wash boarding" (the corrugated cardboard core imprints through the outer sheets) on the surfaces of cases that are manufactured of corrugated cardboard made of recycled Kraft paper (which tends not to be as strong as virgin Kraft paper used in North America).
Case erecting systems using vacuum cups cannot tolerate a substantial amount of downward or upward force on the cases. Since considerable force is required to bend the major and minor flaps of an erected case under the case, it is not uncommon for cases to break away from the suction cups when the cases are lowered onto or struck by the flap tuckers.
Conventional case erecting systems, in order to enable the major and minor flaps of the cases to be secured by adhesive, must be completely opened, and then completely closed, thereby necessitating lengthy case erecting lines to carry out these operations.
Adhesive applicator systems used in conventional case erecting and sealing lines are heavy, bulky, and expensive, cannot operate effectively in confined spaces and can only handle hot melt adhesives at the speeds of today's case erecting lines.
Conventional case erecting and sealing apparatus use substantial quantities of expensive hot melt adhesive, and consume large quantities of valuable energy in order to function.
Conventional case erecting lines are noisy, dusty, and become adhesive laden because of stray droplets of adhesive that miss the flaps of the cases and collect on the various pieces of equipment, and in the case of hot glue, cause stringing or webbing.
The large distances customary with conventional case erector and sealing lines necessitates cases being moved through substantial distance which is energy inefficient.
The adhesive systems used in conventional case sealing lines tend to create rebound from the flaps onto the spray head and free floating adhesive droplets, thereby tending to clog the nozzles of the spray head, and creating irregular spray patterns which cause sealing problems for the case sealing line.
Conventional case erector and sealing systems require 1/2 hour to 1/2 day down time in order to set them up for a second size of case following processing of a first size of case.